Toshiba GR200 Series - (ii) Characteristic of Inflowing and Outflowing currents plane

6F2S1914 (0.49)
GRL200 (Soft 033 & 037)
- 27 -
The characteristic A and B both are expressed using the following equations:


  

 
(2.2-1)


 

 
(2.2-2)

󰇛
  
󰇜
 󰇟DIFL-I1󰇠
(2.2-3)

󰇛
  
󰇜
 
󰇟
DIFL-I2
󰇠
 󰇛  󰇜  󰇟DIFL-I1󰇠
(2.2-4)


󰇟
DIFL-Slope1
󰇠

(2.2-5)


󰇟
DIFL-Slope2
󰇠

(2.2-6)
Equation (2.2-1) and (2.2-2) shows the characteristic A and B, respectively. The user can
set minimum internal fault current using setting [DIFL-I1]. The user can set the knee, which
is referred as crossing point characteristic A and B, using setting [DIFL-I2]. Restraint settings
of the characteristic A and B in percentage are available using settings [DIFL-Slope1] and
[DIFL-Slope2].
(ii) Characteristic of Inflowing and Outflowing currents plane
Figure 2.2-2 provides another expression corresponding to the Figure 2.2-1; the characteristic
is expressed on the plane between the outflowing current (I
out
) axis and inflowing current (I
in
)
axis. Regarding to the I
out
–I
in
plain, the DIF operation is performed in the hatched area of
this figure.
Figure 2.2-2 Segregated-phase current differential element (I
in
-I
out
Plane)
X
I
in
I
out
Y / (1 + β)
o
1−α